


The King of Rot

by rockafansky



Category: Ao no Exorcist | Blue Exorcist
Genre: Blue Exorcist OVA 10, Implied Demon Yukio, POV Second Person, POV Shiratori, Post-OAV/OVA, Shiratori Redemption, Shiratori's basically a walking demon hotel
Language: English
Status: Completed
Published: 2017-07-18
Updated: 2017-07-31
Packaged: 2018-12-03 14:49:54
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 9,993
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11534478
Author URL: https://archiveofourown.org/users/rockafansky/pseuds/rockafansky
Summary: After months of recovery from an accident he doesn't remember, Reiji Shiratori is finally ready to start school at True Cross Academy. And so, it seems, is the demon king lying dormant inside him.





	1. Wraith

**Author's Note:**

> YOU GET A REDEMPTION ARC! AND YOU GET A REDEMPTION ARC! AND YOU-

Your name is Reiji Shiratori, and today is a very important day for you.

You’re in the eleventh grade at True Cross Academy, a prestigious high school in Tokyo, and it’s just about as amazing as you’ve anticipated. These hallowed halls feel like they have a lot of stories to tell. Earlier this morning, your enthusiasm struck your parents as kind of strange for you. Junior high was relentlessly dull, so you didn’t make a habit of attending class, but something about this place really has you excited. After all these months, you can’t believe you’re finally here.

You should have started at True Cross last year, but you had an accident before you enrolled, so this is the very first time you’ve been on campus. It’s also the first time you’ve left your house in quite a few weeks; you haven’t gotten out much since you got hurt. Although you don’t quite remember what happened during that time, after that incident, people often say that you’ve changed.

You really wish they would be more specific.

You’ve had a lot to think about lately. But lucky for you, your new education situation is overwhelming enough to take your mind off things for a while. The brochures really weren’t lying about how grand the place is. Buildings full of history, and students full of elegance. Somehow, you don’t feel like you quite fit in among all of your new classmates. But maybe that’s just because you haven’t tried speaking to anybody yet. You take a deep breath, shake off your first day nerves, and wonder what kind of interesting people you’ll meet today.

You don’t have to wonder for long. Distracted by the academy’s fine architecture, you slam right into an interesting looking person as you’re crossing the threshold.

“Hey!” He’s a boy your age. “That hurt, be careful.”

“I-I’m so sorry.” You can’t believe it’s day one and you’ve already managed to make a fool of yourself. But before you can scold yourself too harshly for it, you realize that the guy you crashed into wasn’t a stranger. “You…you’re…”

He seems to recognize you, too. “Oh! Aren’t you Shiratori? You’re healed already?”

You nod. “Y-yeah, fortunately.”

Whatever history you two have, it must not have been a positive encounter.

“You’d better not cause any more trouble,” says the boy, giving you a warning look. “See you.”

“Y-yes, thank you very much,” you say as he leaves. Geez, you guess even a place as incredible as True Cross Academy has a person with a bad personality.

As you continue on your way to class, you’re still wondering just where you know him from. You have a lot of partial memories like this, from before your accident. There are plenty of things that seem familiar now that shouldn’t be. But now that you think about it, you remember seeing this guy before. But who was he?

_Oh yeah_ , you think suddenly, stopping in the hallway. _He’s Okumura-kun_.

You don’t question where the name came from, what it means, or why you remembered it. It feels like you’ve known it forever. Could he be a family friend? That might be it, but you don’t feel like entertaining the uncomfortable notion that your memory loss might’ve stretched further back than you thought. You still feel somewhat confident in your ability to identify old friends and foes, even if it’s been a while. So which is he to you?

_That’s right, he’s Okumura-kun._ You toss the name around in your mind, trying to figure it out as your peers file into their classrooms. _Okumura-kun. Okumura-kun. Okumura…Okumura. Okumura. Okumura._

“Okumura!” you shout, or maybe it’s not you. Okumura-kun is already too far away to hear. “Oku—”

“Please don’t shout in the halls.” You’re interrupted mid-screech by a goateed man in a trenchcoat. His eyes are stuck to a worn-looking journal, but he’s holding up his hand at you like he’s some kind of crossing guard. “Class is in session. What’s your name, boy?”

You are not the same being you were five seconds ago. Something has awakened inside of you; something that has been lying dormant for many months. Now that it’s aware and alert and very much alive, it has taken control. With this new presence comes a new name: _Astaroth_. You want to scream this name from the tallest spire of True Cross Academy and watch from above as it rings through the campus town. You want to infect this place with the festering heat of decay and look on as its halls cave in around you. You want to level classrooms, to mash every dorm into rotting wood until you find what you were sent here to retrieve.

Of course, you can’t tell any of that to this teacher, because he’s really not paying you much mind. It will give you great pleasure to see him kneeling before you.

“My name is—” Suddenly, you catch a glimpse of the pin glimmering on his chest. Very much like the one _that_ person held, as he didn’t-quite-banish your existence to Gehenna.

_Exorcist._ The memories return all at once, and next to the blissful mediocrity of your host body’s insignificant life, they are immensely painful. You take a deep, deep, deep breath and calm down.

“My name is Reiji Shiratori.”

“Well, Shiratori-kun,” says the exorcist without looking at you. “It would be a shame to earn yourself a record on the first day of school. Head to class.”

“Yes, sir,” you say in your best impression of Reiji Shiratori. The exorcist goes on his way, and you wonder how in Assiah you were able to get past him without him noticing your horns.

You haven’t lost track of Okumura. To senses as finely tuned as your own, the kid is practically a fiery blue homing beacon. But as you sift through your options at this moment in time, you have to recognize that if there’s one exorcist on campus, there’s bound to be more nearby. And after your two unsavory encounters with these people last year, you’re not overly eager to meet any more of them.

With some reluctance, you give up the chase for now, tearing your focus away from the alluring presence of the prince of Gehenna and trying to figure out just what it was Reiji Shiratori was so excited about doing a minute ago. After exploring the recesses of the kid’s mind, and considering your current location, you realize he was probably about to go to class.

In no time at all, you decide that it’s the worst idea you’ve ever sunk low enough to consider. What’s the King of Rot going to do in a high school classroom? In this life, the depressing realities of an existence led between the realm of the living and the dark expanses of Gehenna have been your teacher. If you’ve got some spare time in the material world, you’re going to spend it eating Japanese street food.

 

It takes a long time for night to fall in Assiah. For all of your years spent in the cool darkness of your home dimension, you didn’t imagine any place could spend such a long time engulfed in the light of a burning star. After over a year of dormancy in this world, you hope your master doesn’t think you’ve forgotten your purpose.

You find the young prince’s location without much difficulty. He seems to be living alone, in an abandoned dorm on the edge of campus. You can’t believe your own luck. You take it as a guarantee that there will be no exorcists around this time to disrupt your mission.

The lock is easy to break. Lots of things are easy to break, with your strength. You encounter a sleeping demon in the kitchen, that doesn’t wake when you pass. You also run into a cluster of coal tar in the hallway. They gravitate toward you like moths to a flame. Like plenty of other old buildings, this one is teeming with demon activity. But there’s only one demon that interests you tonight.

He’s fast asleep when you crack open the door of his room, which isn’t much cleaner than the rest of the building. You shudder violently as a wave of displeasure crashes over you, causing your fangs to elongate and your body to expand.

_Yes, this is Okumura._

The back of your school uniform rips open, but he doesn’t wake. You suppose it would be more convenient to transport him to Gehenna in his sleep. All the same, before you take prudent action to get the young prince to his family reunion, you’re struck with a longing to relish his panic when he awakens to your smiling face. The thought is too delicious to ignore. You reach out with one clawed hand.

The sound of a gunshot shatters the late-night silence, your reflexes throwing you away from the bed. The bullet passes so close to your head that you can feel its burn. The second shot grazes your horn as you stumble over a desk chair in the dark.

“Rin!” The voice from the bed is unfamiliar. “Get out of here, now!”

“What’s going on!” shouts a new voice, which you connect to another high school boy. All of them look pretty much the same to you. But as you lie blinking in the darkness, the new kid’s eyes give away his royal status immediately. _This_ is your true target, Rin Okumura. His face has just the expression of half-asleep terror that you had been hoping for. How could you have made such a mistake?

“I’ve been very patient, young prince,” you say, rising from the floor. “But it’s time for you to come with me.”

You’re speaking to Rin, of course, but your eyes never leave the other one. You strain to find the flames of your master behind those rectangular glasses; what you find is very perplexing. The heir apparent is still your primary objective. But, now that you’re here, you suppose you’d better bring his brother along, too. After all, two Okumuras are better than one.

“My prince, you must—” The younger Okumura’s gun arm snaps up, ready to put a bullet in you, but Rin quickly blocks his attack with his body.

“Yukio, wait!” he says. “You can’t shoot him. This guy goes to our school!”

“It’s the third time Astaroth has taken control of his body,” Yukio regards you coldly. “We can’t assume the host is still alive.”

“But I—” Rin protests. “I talked to him this morning. He was fine then!”

“That doesn’t mean anything,” says Yukio, but he looks unsure.

_Thank you, Reiji Shiratori_ , you think, your eyes locked on that gun. _Tonight it is incredibly convenient that you are usually a human that looks and acts like a human._

“Look at that, little brothers,” you say, flexing your claws. “You can’t hurt me without hurting your classmate. What can you do, but give in? Is it so much to ask that you spend a little time with your family?”

“You—!” Rin lunges at you, but Yukio’s arm holds him back this time.

“Lord, hang a millstone around his neck so that he may never again rise from the depths inhabited by—”

You howl with laughter. “You think that worn out old verse is going to stop me? It didn’t do much good last time!”

“Unable to see, unable to hear, imprison him in—”

“Right, that’s enough,” you say, lunging at his throat with your claws. Yukio doesn’t quite manage to dodge in time, dropping his gun as the two of you tumble to the floor. He loses his glasses in the fray, the lenses shattering where they land. Rin gives a shout of alarm and, with a burst of unholy blue flame, unsheathes his sword. You’re ready for him this time, though, and the sound he makes when he smacks against the wall is worth the fear of punishment.

Yukio cannot speak in his current position, but his hands move quickly to the holster at his belt. You pin his arm to his side, expecting he’ll try to draw another gun. But instead of a firearm, he squirms under your pressure until he can unearth a small vial of reddish liquid. Before you can wonder what’s inside, he flexes his wrist hard and smashes it on the floor. You recognize the scent of blood immediately, a different kind than what’s flowing from the fresh wounds on Yukio’s hand.

The windows both shatter at once, and two shadowy forms sail into the room like monstrous birds, one slamming into you like a heavy punch in the gut. You hit the floor with a grunt; your body is powerful, but still unmistakably human. In the chaos of the shadow beasts’ arrival, the Okumura brothers manage to get back on their feet.

“The hell are these things?” says Rin, backing up against the wall.

Yukio ducks, letting one of the shapes fly over his head. “Wraiths. Some call them shadows of the dead, attracted to the scent of human blood and the prospect of a living body to host them.”

“Right, I shouldn’t have asked.”

The wraiths swirl around you as if searching for an opening. Their presence makes the room feel icy; the hairs on Reiji Shiratori’s arms begin to stand up. Your claws scrape the floorboards as you return your body to its feet. Once you start to laugh, it’s hard to stop.

“You think a couple of wraiths are gonna get the best of me?” you say, grinning at Yukio while the shadows circle you like vultures. “Twice already I’ve been exorcised from this body, and each time I’ve come back stronger than before. It’s as if he wants me here!”

“So you have an easy host,” says Yukio. “That’s good for you. But—”

“But what, Four-eyes?”

“But it’s good for _them_ , too.”

With that, he uncorks another vial from his holster and throws its contents toward you. Before it crosses your mind that maybe you should be worried, the wraiths go crazy, enveloping you in their darkness as they go for your mouth, your eyes, any available orifice. You stagger backwards, howling, broken glass crunching under your sneakers.

Before you know it, you are unable to move.

“What’s happening to him?” asks Rin from somewhere very far away.

An equally distant Yukio answers. “Wraiths will fight anything for control of an available host. I doubt they’ll win against Astaroth, but it should give us enough time to restrain him.”

“Shiratori-kun…” starts Rin. “Is he going to be okay?”

“I can’t say for sure,” says Yukio. “But his well-being should be the least of your concerns right now. There could be more like him coming for you.”

“What am I supposed to do?”

“The smartest thing to do would be to get out of here immediately and find somewhere safe to hide.”

“Like that’s gonna happen,” says Rin. “What else?”

“Your other option,” Yukio looks at you. “is to shut up and help me lift him.”


	2. Coal Tar

You wake up after what must have been the most boring school day of your entire life, because you don’t remember any of it. A piece of lined paper sticks to your face when you lift in from your desk. You are the last person in the classroom, and nobody bothered to wake you. Figures.

You had friends, once. Just last year, you and your gang were the talk of the town. Or at least, that’s what you liked to think, and what you liked to tell girls. But after your accident, your buddies started to act strangely around you. They’d go to great lengths to avoid answering your texts, visiting you at the hospital or at home, or otherwise encountering you in any way. You’re pissed as hell they’ve been giving you the permanent silent treatment, and aside from that, you also kind of miss being doted on. For a while, being feared was a lot of fun. But now, they fear you too much. And you’re still not sure why.

You peel the paper off of your cheek and crumple it into a ball, pulling yourself out of the seat with some reluctance. You’re more tired than you should be after napping the day away, and your head feels like a block of cement. You wonder vaguely if you missed anything important, before your old penchant for slacking tempts you back into idleness.

It’s still light out when you leave the school. There’s something ashy wafting through the air across the street, but you can’t quite make out whether they’re leaves or wisps of smoke from the construction site. You’re thinking about whether or not it’s worth it to stop by the convenience store on the way home when you see them.

Students. Three of them, walking this way.

 _Maybe they forgot something_ , you think, but part of you knows that’s not right. Something seems off about them. You pull out your cell phone, somehow still fully charged, to check the time.

The device nearly slips out of your hands.

 _8:02 am_. You were at school the entire night? Your parents are going to waste you. Cringing, you risk a quick scroll through your messages, but you find none of particular concern from your mother or father. You let out a short sigh of relief. Thank God for their busy schedules. They must not have noticed you were gone.

Does that mean you slept for almost twenty-four hours? It doesn’t make sense, considering how tired you are, and how hungry you’re not.

You’re tempted to blow off school today; as of day two, you’ve already spent more time in the classroom than any of your peers. But disappointment over not getting the high school experience you’ve anticipated eventually wins out over laziness, so you try to ignore your dark feelings. You were excited about this place yesterday, after all. You chalk it up to the bitterness of being left behind, turn on your heel, and march right back into school.

 

The morning passes without incident, if you don’t count the killer migraine that’s taken root inside your skull. Class is overwhelming; it looks like you slept through multiple assignments yesterday. Even though this is your first time making an effort to regularly attend school since you were a little kid, you’re still pretty embarrassed that you’re so behind on only the second day. Even worse, going to a teacher for help catching up would mean admitting you slept through their class. And it’s not like your friends are around to give you a hand, either.

That’s what you think, until you see a familiar face in the cafeteria line.

“Oi, Adachi!” Your former friend jumps at the sound of your voice, and for a second it looks like he’s going to bolt.

“Shiratori-san!” he stammers out your name. “Wh-what do you—Are you—”

You sigh, rubbing at your aching head. “I missed history yesterday. Math, too, and I’ve got that next. Did we have homework?”

The uninteresting nature of the conversation seems to relax Adachi. Still, rather than answering directly, he narrows his eyes at you, like he’s trying to figure you out.

“Have you been, uh, okay?”

“You don’t have to do that,” you tell him, slightly annoyed. “I know you don’t want to talk to me. I won’t bother you again if you’ll just write it down.”

At first, he nods, fishing a pen and paper out of his blazer. But after a moment of scribbling, same as always, the silence is just too much for him.

“You watch the _Puni Puni Poemy_ rerun?”

“I’m telling you, just write it—” You stop for a second. “Wait, you’ve already seen that? I thought it was on tonight.”

Adachi shakes his head. “Two days ago. You must’ve gotten the air date wrong.”

“No, I did _not_ ,” you say, pulling out your phone.

“O-okay, you’re probably right!” Adachi stammers. “I’m so sorry.”

“Cut it out,” you say blankly. “Just cut it out.”

He’s right, though. The time of day isn’t the only thing that’s off; according to your lockscreen, it’s _Thursday._ If sleeping really is all you’ve been doing, then you’ve been out cold for almost three days.

“Are you sure you’re okay, Shiratori-san?” Adachi shifts his weight nervously. “You’re acting weird.”

“ _I’m_ acting—You’re the one who’s being weird!” you get out, causing more than a few glances to shift your way. “How come everyone’s been ignoring me all this time?”

Adachi gets a little braver, now that you have an audience.

“You don’t know why?” Of course you don’t know why. The only memories you have surrounding your accident involve waking up in a hospital room with eleven broken bones and one mysterious burn scar. As for the days leading up to this incident, you were left with nothing but questions.

“Tell me.”

“You…” He takes a breath. “I watched you try to gouge Okumura’s eyes out with a metal bar. Then you punched a huge dent into the side of a dumpster, screaming about how you were going to hunt him down. ”

“That wasn’t the kind of thing we normally did?”

“Fuck no! You were acting crazy.”

“I’m not crazy.” You used to be able to say this with certainty. Now you aren’t so sure.

“We still don’t know what was going on with you then,” Adachi shakes his head. “So how are we supposed to believe that things are any different now?”

“I…” You wish you could refute him, but you don’t have any proof that he’s lying about you. Instead, you clench your fists and throw in the towel.

“Who the hell cares what you think, anyway?”

You grab the paper from his hands and storm off to do your damn homework.

 

By the time History begins, you’re still working on yesterday’s math assignment. What does Adachi know? Besides the correct date and the page numbers for the homework you missed. You wish you could ignore what he said as easily as he and the others have been ignoring you lately.

_What could I have been doing for the last three days?_

Your classes are held in one of the oldest buildings on campus, and it’d be a pretty space, if not for all of the weird dust that’s floating around here. You find yourself more focused on the shapes of the black particles than on what the teacher is saying. More than once, you could swear you see one change direction. Maybe you really are going crazy. Or maybe you need to start wearing your contacts more often.

Halfway through the class period, the door opens slightly.

“Sorry, Fujiwara-sensei.” A soft voice, tentative. “I had to visit the nurse.”

“That’s fine, Hirai-san.” The teacher excuses her. “Please take your seat.”

You lean back in your chair, curious about this classmate you’ve never seen before. Or can’t remember, depending on whether you’ve experienced a legitimate absence or just another lapse in memory. Just thinking about it makes your brain hurt.

But soon your headache is the least of your worries. The moment the student pushes open the door, the dust particles swarm her.

“Aagh!” You almost fall out of your seat, screaming.

“Shiratori-san?” The history teacher seems more surprised than angry. “What’s wrong?”

“She’s—she’s—!”

You can’t tear your eyes from your classmate, covered head to toe in a churning mass of black dust. There’s no mistaking their movements now. Every piece of dust in the room is flocking around her like piranhas to their next helpless meal. The girl makes no motion to run or scream; she must be in shock. Your heart pounds in your ears.

“A-are you okay?” she asks you, and the particles fly into her mouth like insects.

Your stomach turns. Feeling the heat of your classmates’ stares, you push your chair back from your desk, nearly tripping over it in your haste to get up and get the hell out. Someone in the back of the room snickers.

The teacher follows you out the door. You lose him in about three corridors. Now you’re lost, too, but you don’t care. You’ve apparently already spent three nights at this school, and you’ll easily spend another before setting foot in that classroom again. You sink the floor, running your nervous fingers through your hair.

_What the hell is happening to me?_

 

You do manage to find an exit, before the school day ends. After an unnerving trek home and an utterly sleepless night, you return to school to find that numerous rumors about you are bouncing around campus. Despite True Cross Academy’s large student population, weird news travels fast. You start to hear the whispers in first period; by second, you feel eyes on you as you swat animated dust particles away from your face. Third, you don’t want to talk about. By fourth, you’re wondering if you should have taken the day off.

Your classmate, Hirai, is noticeably absent. You wonder if she’s dead. You wonder if anyone else in the class saw what happened to her. Probably not, considering you were the only one who flipped the fuck out about it.

You sit alone at lunch, busy finishing all of the work you missed. It takes the life out of you quickly, and after a while you decide to sit back and people-watch instead. You’ll have plenty of time to focus on schoolwork when you’re home, safe, and far away from whatever other monsters this school is hiding.

Disappointingly, your people-watching doesn’t deliver much in the way of familiar faces. That is, until your eyes land on Rin Okumura.

The sight of him makes you feel slightly nauseous, but you’re not sure why. You teeter slightly in your seat on the stairs, trying—and failing—to recover any lost memories of him. You vaguely remember this punk from your old neighborhood, but you’ve never spoken to him until a few days ago, when you bumped into him in the hallway on your way to class. Now that you think about it, that’s the last thing that happened to you before your school life took a turn for the weird.

You decide, desperately, that he must know something.

“Okumura-kun!” You catch up with him in the hallway.

“Oh, Shiratori-kun.” He doesn’t seem surprised to see you. “How are you feeling?”

 _Damn, he already knows_. “You heard about it too, huh?”

He shrugs. “You made a pretty big scene.”

“I must be losing my mind,” you say. “That day, when I was in class, I _saw_ something. Something terrifying. You have to believe me.”

“Sure, I believe you,” Rin looks around. “I knew you’d probably start seeing demons after what happened the other night. But I didn't think a guy like you would be so afraid of them.”

“I-I’m—” You start to protest, before it really sinks in. “Wait. _Demons_?”

“That’s what I said.”

“You’re trying to trick me.”

Suddenly, Rin grabs the edge of your uniform shirt and yanks it up, revealing the burn scar above your hip. At first, you’re too shocked to react.

“If I was lying to you, how could I know about this?” he asks.

You jerk away from him, pulling your shirt back down. “The hell was that for?”

“You know where it came from?” asks Rin.

“No, it just showed up,” you say, feeling violated. “I don’t remember getting burned.”

“It’s a brand. My old man put it on you last year, to make sure you wouldn’t get possessed again. But I guess that didn’t work as well as he’d hoped.”

“It didn’t…work?”

“Couple of nights ago, it happened again. You were possessed by an upper level demon, who snuck into our—” Rin breaks off, shaking his head. “But that’s not important. What’s important is, this was the third time I’ve seen you possessed by the same demon.”

“And the first time was…before my accident.”

“It was no accident.” Rin shrugs. “Astaroth almost destroyed you.”

You wince. “That name…”

“He’s the one,” says Rin. “The King of Rot. If we’re lucky, you’ll never have to deal with him again.”

“But if he’s really possessed me three times…”

“Some people are just easier to control than others,” says Rin. “You've probably just got a personality that makes you more appealing to demons."

“What does that mean?” You feel like his words should piss you off, but they don’t. He’s just confusing you.

“It means you're probably better off not knowing." He leaves it at that.

“You’re angry at me,” you say. “Why? Is it because of something that demon did?”

“Who’s angry?” he says, obviously lying. “It’s just weird to have a normal conversation with you, after everything that’s happened.”

“This…is a normal conversation?” you stare at him. “You’re telling me I was possessed by a demon three times without even knowing about it, and this isn’t weird at all for you? I almost died!”

“I mean, yeah, _almost_ ,” he says. “Yukio’s probably the only reason you’re still alive. So think about that next time you want to diss him for being here on scholarship.”

“But I’ve never—”

“Yes,” says Rin. “You have.”

“I see.” So that’s why he’s pissed off. Not because of anything you did as a demon, but something you said as your regular old self. Figures.

“Anyway, if that’s all, I should get to class,” says Rin.

“Wait!” you say, “What about the demons in my classroom?”

“What about them?”

“You obviously know a lot about demons. Much more than any normal human should…” you say, looking at him. “You have to be some kind of Exorcist, right?”

“Heh. Of course!” He seems to perk up. “That’s me. An Exorcist!”

“In that case…” you say. “Please, help me rid my classroom of these demons. They attacked this girl yesterday, and today she’s not at school. I don’t want it to happen again.”

Rin looks at you, and maybe he senses that you’re being earnest.

“Sure,” he says. “You can count on me.”

 

Whether he’s eager to show off his Exorcist knowledge or just for an excuse to ditch class, Rin comes with you to your classroom in the old part of campus. You become much quieter once you begin to see the dust particles around, but none of them seem to be moving in any threatening way. It still jostles your nerves to be surrounded by them, though.

Nothing happens for a long time. Rin spends the majority of the class period trying to get the attention of the student sitting in the row in front of you, a tall guy with a blond streak in his hair. After a while, it seems almost like he’s ignoring Rin's efforts on purpose.

“So, where’s this demon?” Rin asks you. You can’t take your eyes off of Hirai’s empty seat.

“Just wait.”

Sure enough, as history class is coming to an end, the door cracks open, and the dust particles go crazy. You go rigid in your seat, gripping the bottom of your chair until your knuckles turn white. Hirai takes her seat, and class resumes as normal.

“Wow, that’s a lot of coal tar,” says Rin before turning back to you. “So, demon? Is it coming?”

“Th-that’s it,” you say in disbelief at his calm. “They’re right there.”

“You mean the coal tar? Those are basically harmless.” Rin shrugs. “I’m not sure why they’re all over her, though.”

At this, the guy with the blond streak turns around in his seat, looking slightly annoyed.

“Coal tar are tiny demons that enter this dimension by possessing fungi and bits of dust. They tend to cluster in dark, damp places and they're attracted to introverts, or people with dark natures. It's not uncommon to see them gather around humans like this.”

You blink at your classmate. “You know about this, too?”

“That’s our Bon,” says Rin. “So studious.”

The guy sighs. “Maybe if you didn’t keep fallin' asleep in demonology class—”

“Hey, wait, wait,” you interrupt. “How many of you are there?”

“Shiratori-san! Suguro-san!” Your head snaps back to the front of the classroom, where the teacher is staring at you both. “Pay attention, please.”

You spend a few minutes in silence before Rin makes another observation.

“Now that I think about it,” he whispers, poking at a coal tar with the end of his pencil. “There were plenty of these guys around you last year. But now, not so much. What do you think it means?”

You can’t seem to find the words to respond. Suguro does it for you.

“If anythin', it means his lungs aren’t gonna rot. It’s dangerous to breathe those things in, you know.”

Your eyes return to your other classmate, who’s still surrounded with tiny demons. “Then Hirai-san—”

“She'll be fine,” he says, turning back around. “I noticed her the other day, and asked Okumura-sensei about it. With coal tar in those kinds of numbers, it’s no wonder she’s making constant visits to the nurse’s office.”

“You’re the teacher…” You look at Rin in awe.

“Ha!” says Rin. "Of cour-."

“No,” Suguro cuts in. “ _Yukio_ had me put her in contact with him. He’s working on a mask that will repel them, so maybe her lungs can begin to heal."

“Impressive,” Rin blinks. “She must be the only girl my brother’s ever given his number to.”

Suguro half-smiles. “Yeah, that too.”

“So, these coal tar…” you say. “That’s all there is to them?”

“They’re usually harmless.” Suguro nods. “But you can’t just ignore 'em. They’re the kin of Astaroth, after all. They produce all kinds of crazy decay.”

 _Astaroth_. Your head begins to pound again. “I see…”

Rin’s looking at you funny. You guess he’s aware, more than anybody, that the coal tar aren’t the demons you’re most worried about.

**Notes for the Chapter:**

> Next Chap: You begin to stalk the Exorcist cram school kids.


	3. Astaroth

**Notes for the Chapter:**

> Sorry for the wait. Shoutout to my one commenter for getting me working on this again! This will (probably) be the last chapter of this fic. Hope you enjoy~

“You…are not a demon.”

It’s very early in the morning, and you’re spending the extra time you have before class talking to yourself in the bathroom mirror. You realize that doing this makes you look a little bit ridiculous, but after everything that went down in your classroom the other day, you’re far past caring what your classmates think of you. Recently you’ve made these few minutes of weird self contemplation a part of your daily routine, and it’s helped you a little bit, just seeing your normal reflection looking back at you.

Of course, you have no idea what you looked like while you were possessed. That might be a good question to approach Rin or Suguro with, but it doesn’t seem like they’re overly concerned with you anymore, now that you’re no longer hosting an all-powerful demon king. So they probably don’t want to talk to you.

“You don’t look like a demon.” You tilt yourself closer to the mirror, leaning on the edge of the sink. You look the same way you always do. As far as you know.

The more days that pass between you and the incident, the more demons seem to be popping up around you. None of them attack you or are otherwise vicious, and no one, not even your Exorcist classmate, takes much notice of them. You get the feeling that you’re just going to have to learn to live with them. Harder to ignore is the fact that Hirai has been absent from class for the past few days.

“But you wouldn’t _know_ if you were possessed by one, would you?” you demand of your reflection. This isn’t helping.

You lift up the edge of your shirt and examine your brand in the mirror. Now that you’re really looking at it, you can almost make out some of the imagery. Animals, maybe? But the mark itself is only the size of a poker chip, and the details are too vague to see. Maybe that’s why it didn’t work the way it should have.

What could Yukio Okumura have done to you, to banish Astaroth for good? You wonder if whatever it was will work any better than his father’s methods did. Or more accurately, you wonder if he will fail in the same dangerous way. As much as you want to trust Rin’s word, you’ve always been a hands-on learner. You simply can’t move forward without proof.

So, like a rational human being, you begin to stalk your Exorcist classmates.

Suguro is easy; the two of you couldn’t avoid each other if you tried. Studious as he is, you’re hoping to catch a glimpse of some ancient texts or mystical scrolls or, hell, a copy of _Exorcism for Dummies_ , as he reads during class, but you’re out of luck. The only materials out on his desk are his textbook and his notes; he seems to keep his subjects separate. He notices you looking over his shoulder after about the third time, and gets pissed because he thinks you’re copying his notes.

For such a straight-laced guy, you find him extremely intimidating. Asking him one of your many questions seems pretty impossible.

Rin is tougher to locate, since you don't know his schedule, but you do see him at lunch. You take note of the people he hangs around; Suguro is one of them. Another two boys sit with them, as well as three girls. Are these students studying to become Exorcists as well? They look like regular high schoolers to you. One of the boys has bright pink hair, and one of the girls is wearing a kimono instead of the True Cross Academy uniform, but aside from that, there’s nothing particularly odd about any of them.

Determined to prove your theory, you begin to follow them everywhere. You become familiar with their schedules. You sit within earshot at lunch. You even get up from your seat during class and follow Suguro to the bathroom a few times by accident, convinced he’s heading off to…you don’t know, do some exorcising? You’re not entirely sure how all of this works. Nevertheless, it’s a welcome distraction from the ridicule of your peers, who still haven’t forgotten about your little episode in class the other day.

Each day, you pick a student to tail after school, just to see where they go. At lunch, you often overhear them discussing cram school, which you suppose is a normal enough student activity. But if not during cram school hours, when else are they supposed to study demons? You’ve already ruled out the school day—you and Suguro are together for all of your classes. So you figure that they must get to their Exorcist studies later on, during cram school hours.

The only problem with this theory is that you can’t seem to figure out where their cram school classes are held. Every time you follow one of them after school, you lose track of them before you can figure out where they’re going. They all seem to be heading different places, too. Suguro walks to the newer part of campus. The pink-haired boy goes back to the dorms. Two of the girls head to the gym. And then, each day, your investigation culminates in the same brand of failure. Inexplicably, you lose them.

One day, you watch as Rin unlocks the door of a staff bathroom and disappears inside. You’re taken aback, until you remember that his brother apparently teaches at True Cross, as if being an honor student there wasn’t enough. That means he would have been issued a bathroom key. Rin must have lifted it off of him or something. You lean against the wall and wait for him to come out, absentmindedly flicking through your Twitter feed.

But then he doesn’t come out, and you start to wonder if he even plans on going to cram school today. You knew him in middle school; his attendance record was worse than yours. Frustrated and past the point of caring whether your cover is blown, you give the door a knock. No response.

“Ridiculous,” you grumble, giving the doorknob a try.

It turns completely on your first go. The door is unlocked.

You blink. Something about this gives you a bad feeling. Against your better judgment, you turn the knob again and push open the door.

There’s no one inside.

“Okumura-kun?” You turn around and around, searching for a door, a cabinet, an opening of any kind. But you find no exits, no hiding spots; there’s nowhere he could have gone.

 _He must have left while you were looking at your phone._ You know he didn’t. You know you would have seen him. But it’s the only explanation you can come up with, so you try to make yourself believe it. Maybe it’s time for you to go home.

Another person might have been put off from the investigation by such a strange experience, but it only makes your curiosity stronger; and, to a greater extent, your fear. If a person can disappear from a restroom without using the door, you don’t want to imagine what a demon can do.

The time you don’t spend tailing the cram school kids, you spend absorbed in your demon-related anxiety. Every shape and shadow in the darkness is out to get you now. You see demons inside lockers. Under benches. Weaving their way through students’ legs as they walk to class. They take many different forms, but you’re loath to get too close to any one of them. To your classmates’ amusement, you even begin to sway from side to side rather oddly as you walk, to avoid running into coal tar.

 _The kin of Astaroth_ , you think as you duck out of the way. They already got Hirai. Maybe you’re next in line.

After a few weeks of this, your Exorcist classmates begin to get used to your persistent presence. They never invite you to join their group, and they don’t seem to regard you as anything more than a nuisance, but they’re not quite as surprised when you show up wherever they happen to be. You suppose that’s a good thing.

“Hi, Reiji-kun,” says the girl in the kimono, pretty much whenever she sees you. You realize that, despite your research, you still don’t know her name. You attribute this to the fact that she only ever shows up at lunchtime, usually just once or twice a week. You’re not sure she’s even a True Cross student.

“H…Hey,” you say. It still catches you off guard, that one of them acknowledges you so casually. But then she returns to the conversation, and you return to your lunch, and that’s the extent of your communication.

Despite the fact that you don’t really talk to any of these students, your school life is a lot better with them around. If you run into a demon with ill intent, it’s nice to know that you’ll have a pack of Exorcists right there to save you. In fact, you find it comforting to have at least one of them in your sight at all times. You know, just in case.

They can’t protect you from the rot, though. It all may be a terrible coincidence, but you’ve been having a problem with your lunches lately. Whenever you unwrap your food, whether brought from home or purchased in the cafeteria, it always seems to have covered itself with mold. Disgusted and slightly frightened, you’ve stopped eating at school, save for the occasional snack from the vending machines. You find that you’re only able to safely eat the kind of shit that’s so processed it doesn’t have an expiration date.

You want to tell someone, but after the coal tar incident, your Exorcist acquaintances will probably want to think twice before taking you seriously. You do your best to make yourself believe that you’re just unlucky enough to grab an inedible lunch. Or maybe your lack of sleep is catching up with you, and you’re tired enough to keep making the same mistakes. Maybe the latter would be preventable, if it weren’t for the terrible dreams keeping you awake through the night.

But the worst part of your day, hands down, is your commute. Roughly half a mile on foot, without an Exorcist in sight. Your parents wanted you to live off campus your first year, as there was still some concern about your health in the weeks following the incident—not that they’re around much to look after you. You used to prefer it this way, but now, coming home to an empty house every day is nothing short of terrifying. Who knows what could be lurking in the shadows, waiting for you?

 _You used to be able to protect yourself_. you think bitterly. _What happened to that guy?_

Demons happened, you suppose. And you can’t protect yourself from something you know nothing about.

You’re thinking about this as you enter your classroom on a Monday morning, after another weekend spent locked in your bedroom. Your daily therapy sessions with yourself in front of the bathroom mirror are yielding nothing but the realization that you’ve been looking a bit thinner lately, and you’ve lost some color in your cheeks. You might have to take some time off school if this continues, and you doubt your parents will be understanding.

Someone drops a stack of books on your desk. You jump in your seat, surprised to see Rin and Suguro in front of you.

“Sorry, didn’t mean to scare you.” Rin rubs the back of his neck. “You doing okay?”

“What is this?” you ask, wary. Neither one of them has gone out of his way to speak to you like this since the day they taught you about coal tar.

“These are for you,” says Suguro, nodding towards the books. Then he shoots a pointed look at Rin. “ _Somebody_ neglected to mention that you’ve been possessed three times by a demon king. He was gonna let us all keep thinkin’ you were just another clueless kid with a new temptaint. But that’s not the case, is it?”

“What’s a temptaint?” you ask, feeling dumb.

“That’s _Demonology 101_. Page nine.” Suguro taps the book on top of the pile. “You’re in this deep enough to start doin’ your own research.”

“These are…” You look through the titles. _A Brief Handbook of Exorcism. Exorcistm And The Church. Rituale Romanum._ “These are real?”

“Completely. It’s better than following us exwires around, anyway,” says Rin. “We’ve only been in training for about a year. Anything you want to know about avoiding another Astaroth Incident, you can find in these.”

You pick up another volume. “This one’s just a supernatural manga.”

Suguro gives Rin a look. Rin crosses his arms defensively.

“Yeah, well, it’s pretty spot-on.”

You can’t believe that information like this has just been laid out in front of you. You also realize how ironic it is that the kid you once called a demon is now helping you in the aftermath of your being possessed by one.

“Why are you giving me this?” you can’t help but ask. “You’ve never liked me. Why would you want to do this for me?”

Rin looks at you. “There aren’t a lot of people in Assiah who know that demons exist. It’d be a real waste if the few who did were all terrified of them.”

“I’m not—” You realize how it looks and sigh. “Yeah. I guess you’re right.”

Suguro nods. “And if just knowin’ about them’s not enough…Cram school’s a little light on students, don’t you think, Okumura?”

Rin shrugs. “Eh. Kind of.”

“We’re going to need those books back eventually,” says Suguro. “But for now, study hard.”

You stand up from your seat slowly, nodding as you scoop up your armful of new reading materials.

“Thank you. Thanks a lot.”

“Don’t mention it,” says Rin.

“Where are you going?” says Suguro.

You want to answer him, but you’re already halfway out the door, books in hand, so the only person who hears your response is you.

“Not sure yet.”

 

You ditch class for the rest of the day and do nothing but read until it’s time to go home. You read through lunch, through club period, through cram school, filling your head with information about Assiah, Gehenna, and the mysterious beings that roam between them.

You’ve never been a fast reader, but you’re so invested in the content of these books that you’re able to devote your entire day to them. You learn about temptaints, about possession, about preventative marks and brands, and other various symbols and items that ward off demons. You skim a thick textbook filled with fatal verses, Biblical passages that destroy specific demons just by saying them. For the first time, you’re not dreading your walk home. You know the house will be empty when you get there, so it will be easy for you to keep studying through the night.

Your backpack is heavy, but you feel lighter than ever. You open the textbook in your arms and begin looking over fatal verses again, able to forget your surroundings for the first time in a long time. In your eagerness to get home and learn more, you barely notice the shift in temperature, until it’s too cold to bear. Pulling your uniform blazer closer around you, you start to feel as if you’re being watched. Which, as you cross from the busy footpaths of the True Cross Academy Campus Town to the less populated walks of your neighborhood, is a notion that gets progressively more frightening as you go.

 _It’s fine_ , you say to yourself. _It’s probably nothing_. Amazed by how easy it is to lie to yourself when you’re afraid, you take comfort in all that you’ve learned today. If there’s a demon out there, you’re ready for it.

At least, that’s what you think, until you hear its voice inside your head.

_Reiji…_

Your body immediately goes numb. Your sneakers come to a halt on the pavement, and you stand there for a moment, right in the middle of the street you grew up on, feeling as though someone just jammed the barrel of a gun into your ribs.

“You are not a demon,” you whisper. “You are not—”

 _That’s where you’re wrong._ You can’t remember ever hearing this voice before, but you know immediately who it belongs to.

“Astaroth,” you say, brandishing your textbook like a weapon. “How did you find me?”

 _No offense, kid, but you’re pretty easy to spot._ You feel an unseen hand run through your violet hair, and you nearly drop your book in surprise. You stagger backwards, your heartbeat thrumming in your ears.

“I-I won’t let you take me again,” you say, surprised you can actually speak.

 _I’m afraid you don’t have a choice._ Suddenly, your body seizes up. Spots swim across your vision. Your knees begin to feel very weak, but you keep on gripping your textbook until your knuckles turn white.

“Wh-why…me?” you get out.

 _Why search for another model when you’ve already found the perfect fit?_ Astaroth’s voice echoes inside your head. _Don’t forget how much you needed me, Reiji. You’ve led a miserable existence, relying on your wealth and status to give yourself a leg up. You used the Shiratori name to gain power, allies, a reputation, but it’s never gotten you what you really want._

You squeeze your eyes shut, trying to drive him out of your head. But it’s no use. This isn’t his first time invading your thoughts. He already has you figured out. Frustratingly, it seems as if he knows you better than you know yourself. No matter how hard you rack your brains, you can’t come up with your own answer.

“What…do I want?” You grit your teeth. It’s becoming harder to speak.

 _To be feared._ His voice is louder than your own thoughts. _With your body under my control, I could continue my mission. And as long as I had the reins, no one dared cross you._

What he says is true. When you finally awoke after being possessed for the first time, how shocked you were to find out that all of your friends were terrified of you. Was that what you really wanted? Had you agreed to become a monster just to achieve some semblance of control? How much of the choice was Astaroth’s, and how much of it was yours?

You don’t have the answer to any of these questions. All you know is that it is no longer the truth.

“That’s…wrong,” you say. Your vision is blurring, going dark around the edges. Suddenly, your back arches as if you’ve been grabbed by an invisible hand, dragging your face into the pale light of the streetlamps.

_What did you say?_

“Maybe I don’t want to be feared…” you choke out. At this point, your pulse is louder than your voice, which has been reduced to almost a whisper. You muster all of your strength and yell, “Maybe I want to stop being afraid!”

Suddenly, the tension in your muscles relaxes, and you can move again. You sway slightly from side to side, regaining your bearings as your head pounds like a drum. When Astaroth speaks again, he sounds less sure.

_Let me in, and you’ll never know fear._

Not like that. Never like that. It has to be you, and you alone. You want friends. You want to be the kind of person those friends can trust. You want your family to give a shit. You want to be able to eat your goddamn lunch and sleep at night like a normal human being. And most of all, you want to be strong enough to banish this demon to Gehenna for good.

You open your textbook to the page you’ve bookmarked from every possible corner.

“Evil is in their hearts, O Lord. Give them according to their works, and according to the wickedness of their endeavors.”

_Reiji. Who do you think you are?_

_“_ Give them after the works of their hands, render onto them their reward.”

 _You don’t think that’s actually going to work, do you? Stop it. Stop it now._ Your muscles seize up again, and you almost lose your grip on the book. But something, maybe the last shred of autonomy you have, allows your mouth to keep moving.

“Thou shalt destroy them and shalt not build them up. Blessed be the Lord, for he hath heard the voice of my supplication.”

_Let me in let me in let me in let me iN LET ME IN LET ME IN LET M—_

“The Lord is my helper and my protector. Thou shalt perish where thou standeth!”

For a split second, your vision goes completely white. A primal scream echoes through the street, and you clap your hands over your ears shortly before realizing that you are the one making the noise.

“Shut the hell up!” shouts a neighbor from an upstairs window, as you fall to your knees on the pavement, hugging your book to your chest. It’s over. You realize vaguely how strange the whole ordeal must have looked from an outsider’s perspective, but you don’t really care.

For the first time in months, you feel safe.

 

When you walk into school on Tuesday morning, you feel like you could take on the world. A few of the cram school kids are hanging out by the stairs in front of the school; no one that you know well. You try your luck talking to one of them, failing spectacularly to make friends based on your common demon-slaying interests.

“Guess who exchanged blows with one of the Eight Kings of Hell last night,” you say, quoting your textbook. “It was me. I found his fatal verse in this book and sent him back to Gehenna.”

The pink-haired boy blinks at you. “That’s…uh. That’s great, Shiratori-kun.”

You nod. It is great. Confident he’ll pass the big news on to his cram school friends, you head to class, your nose buried in your book of fatal verses. Never know when you might need to take down another demon king.

“Long night studyin’?” asks Suguro when you take your seat behind him.

“Actually, I…” You rub at the back of your neck. “I turned in early for the first time in ages. Slept like a rock.”

Suguro blinks, confused by your sudden change in attitude. “Huh, so you did.”

“Yeah, I—” You’re prepared to tell him the entire story, but something stops you this time. Maybe being possessed four times by the same demon isn’t the best track record for someone studying Exorcism. You realize that if the pink-haired guy gives a damn, he’ll pass it on to the others. And if he doesn’t, well, maybe it doesn’t matter so much. In the meantime, it’d be nice if things could get back to some kind of normal. So instead of blabbing about your first supernatural accomplishment, you get out your notebook and ask him about his day.

“What’d you do last night?” Immediately, you can tell that you’ve caught Suguro off guard.

“I had class,” he says. “What’s goin’ on with you?”

“What do you mean?”

“You’re actin’ different.”

“Good different, or bad different?”

“Weird different. Want to tell me what’s up?”

At that moment, Hirai walks though the door. She’s wearing a black mask, but looks otherwise normal. Normal, including the dark masses of coal tar that float around her like a cloud of pollution.

“Look at that,” says Suguro. “She’s finally back.”

“About what’s up…” you say. “Could I…Could I tell you about it at lunch, maybe?”

Suguro looks at you. “Sure.”

You give him a curt nod, trying to hide your excitement. He may be an intimidating guy, but he’s really not so bad to talk to. You cross the classroom, content in knowing you’ve kind of sort of got a place at the Exorcist table today. It’s a good feeling.

“Hey, Hirai-san…” you say. She looks up, startled. You can’t quite see her eyes.

“Oh, uh, hi,” she says. You’re not sure if her voice is quiet, or just muffled by her mask. “You’re Shiratori-kun, aren’t you?”

You realize now that the only impression she has of you is from her first day of class, when you began screaming the moment she entered the room. You immediately go red in the face.

“Yeah, uh. I should apologize for the other day.”

“No need,” she says, “Okumura-kun told me everything.”

“Rin Okumura did?” You’re alarmed at how calm she is.

“No, not him,” she tells you. “His brother, Yukio. I didn’t think he was making much sense, but after he gave me this mask, my breathing got a lot easier. So I guess I don’t have any reason to doubt him, or you. You saw what he said you did, didn’t you? Demons?”

You wonder how long it will be before the entire school knows about them.

“Yes,” you say, nodding. “Still, I guess I overreacted. I thought you were being swarmed by insects or something.”

You swear she’s smiling behind that mask. “Yeah, that would really be terrifying. I can’t blame you for freaking out.”

You laugh, cautiously. “That’s definitely what I did.”

She’s nice. Too nice, considering the ridiculous first impression you made. Suddenly, you’re gripped with the urge to reach out to her, to brush the coal tar away from her eyes. The tiny demons float away from your hand with as much resistance as a couple of specks of dust, and you can finally see them. Her eyes are the color of maple syrup, blinking slightly with surprise.

“What…are you doing?” she asks. You realize that you’re being weird.

“Nothing.” You pull back your hand. “Sorry.”

“It’s okay,” she says. “Really. It’s nice to know there’s at least one other person who can see them.”

You’re comfortable enough to smile again. “You’d be surprised.”

**Notes for the Chapter:**

> I'll leave it open like this, just in case I want to write about Reiji hanging with the cram school kids again in the future. If you liked it, drop me a review in the comment box and let me know what you want to see more of; it means a lot to me. Thank you for reading! ~Kato


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